1. Unit 2 Notes: Nervous System Basics Tuesday 2-23-2010

2. (1) Function Respond to stimuli Process information Communicate Maintain homeostasis Basic Pathway: Sensory Input  Integrate & Process  Motor Output

3. (2) Structure Made of: –Brain –Spinal cord –Neurons –Junctions Has a complex organization (hierarchy) of sensory and motor levels.

4. (3) Brain & Spine Brain divided into lobes Spinal cord = communication highway All nerves communicate through Spine Example: Paralysis

5. (4) Neuron Neuron = Nerve Cell Types: Multipolar + Unipolar Basic Structural Components: –Dendrites (Incoming) –Cell Body (Integrate + Process) –Axon (Outgoing) –Myelin Sheath (Insulation + Speed) –Axon Terminal (Final Destination)

8. (5) Unipolar Neurons Use: Afferent Input (Sensory Input) Dendrites connected to sensory organ Message sent to cell body  Out Axon Message sent out of axon terminal FOCUS: –Get message to CNS –Let CNS process and decide (NO need to have cell body right by dendrites)

10. (6) Multipolar Neurons Use: Efferent Output (Motor Output) Multi = Lots of extensions coming from cell body Cell body directly connected to dendrites Dendrites coming from CNS / Efferent path  effected organ FOCUS: –Organize messages by importance –Make organs do things (Important to have cell body right next to dendrites)

13. (7) Junctions Junction = Meeting of Neuron + Neuron or Neuron + Organ –A.K.A.  Synapse, Synaptic Cleft Nerve Impulse  Axon  Axon Terminal  Release Neurotransmitter –Neurotransmitter = Chemical Message –Causes an effect –Binds with cell membrane on other side

16. (8) Nervous System Organization CENTRAL NERVOUS SYSTEM PERIPHERAL NERVOUS SYSTEM (SENSORY / AFFERENT INPUT) PERIPHERAL NERVOUS SYSTEM (MOTOR / EFFERENT OUTPUT) BODY (INITIAL STIMULUS / IMBALANCE) AUTONOMIC (INVOLUNTARY) SOMATIC (VOLUNTARY) PARASYMPATHETIC (REST & DIGEST) SYMPATHETIC (FIGHT / FLIGHT)

17. (9) Sensory Input Afferent Input (away from body) Sends message from body part  Brain Initial stimulus or Imbalance

18. (10) Central Nervous System (CNS) INCLUDES: Brain & Spinal cord “Head Honcho” –Notified of everything, Makes all decisions

19. (11) Peripheral Nervous System (PNS) “Middle Man” / Body Guard: Body—CNS –Helps organize messages being sent to CNS and to organs. 2 Divisions: –Sensory/Afferent Input –Motor/Efferent Output

20. (12) Motor / Efferent Output CNS  Effector Organ –CNS makes decision –CNS sends message to release chemical, or move –GOAL: –GOAL: Regain Balance / Do What You Want 2 Divisions: –Autonomic Nervous System –Somatic Nervous System

22. (13) Somatic Nervous System Voluntary Actions Skeletal Muscle (All other actions are involuntary)

23. (14) Autonomic Nervous System Involuntary Actions –Autonomic : Autopilot –Processes occur naturally without thought 2 Subdivisions: –Parasympathetic Pathway –Sympathetic Pathway

24. (15) Parasympathetic Pathway (Involuntary) “Rest & Digest” Normal bodily functions: –Digestion, Excretion –Lens Contraction, Blinking –Gas Exchange –Sleep

25. (16) Sympathetic Pathway (Involuntary) “Fight or Flight” Bodily Functions during heightened excitement: –Increased heart rate, respiration –Increased sweating –Increased blood flow